1. Field of the Invention
The present invention generally relates to ice makers and more particularly, to a new and improved automatic ice maker for domestic refrigerator/freezers.
2. Description of the Prior Art
Automatic ice makers for use in the freezing compartment of domestic refrigerator/freezers are old and well known; and U.S. Pat. No. 3,276,225 discloses such an ice cube maker which is operated and controlled by electrical power.
Copending and commonly assigned U.S. patent application Ser. No. 081,871, filed Aug. 3, 1987, incorporated herein by reference, discloses an improved version of a modular automatic ice maker known as a single revolution ice maker.
Typically, such ice makers are provided with an electrical resistance heater for heating an ice cube mold which is initially filled with water and then cooled until solid pieces of ice are formed. A thermostat is provided in heat transfer association with the mold to sense the frozen condition of the ice, whereupon the heater is energized for a time period to warm the mold and free the ice pieces so that a mechanical ejector can move into the mold and eject the ice pieces into an awaiting ice bin.
The improved ice maker disclosed in the aforementioned copending U.S. patent application employs a thermostat in heat transfer association with the mold, the thermostat being effective to deenergize the heater while at least a portion of the ice pieces are still within the mold at the beginning of the ejection process and this considerably speeds up an operating cycle of the automatic ice making apparatus. The thermostat has a cut-in or turn-on temperature of approximately 15.degree. F. for energizing the heater after the ice is frozen and a reset or cut-off temperature of approximately 32.degree. F. Thus, when the water in the mold becomes completely frozen forming solid ice pieces and the temperature drops to approximately 15.degree. F., the thermostat closes a switch to supply electrical power to the mold heater and energize the heater. When the temperature reaches approximately 32.degree. F., the thermostat shuts off or resets and the electric heater is deenergized. The mold temperature, however, continues to rise to a value somewhat above the freezing level after the heater is deenergized to free up the ice pieces in the mold so that they may be removed from the mold by rotating ejector blades. In normal operation, the temperature of the mold will not exceed 40.degree. F. and will begin to drop a short time after going above the freezing level. In the event that the thermostat fails to deenergize the heater, however, excessive temperatures could be reached causing damage not only to the ice maker but also, more importantly, to an adjacent portion of a freezer cabinet.